Configure crontab to put to rest a hard disk

Support & Help Requests Hardware
1

Hi all I’ve finished installing Ubuntu 16.04 Mate, and I have met with sguiente problem, previously used to configure gnome-schedule cron now can not not in the repositories. Do not know how to do the following: desire to put to rest a disc and do the 15 minute of every hour in every day. What I have done, without success, it is the following:
I have run crontab -e in the terminal and added:
15 * * * * / sbin / hdparm -y / dev / <hard_drive>
Could you help me. Thank you.

P.D. This problem is also have put in section discución is Spanish.

2

For if it helps someone I’ve solved as follows (if not correct, but it works)
Run from the terminal:

sudo crontab -e and adding the line:

15 * * * * root / sbin / hdparm -y / dev / [disk]

Also crontab -e and adding the line:

15 * * * * [user] / sbin / hdparm -y / dev / [disk]

I find that these lines exist in the archives:

/ Etc / contrab

/ Var / spool / cron / crontabs / [user]

/ Var / spool / cron / crontabs / root

And finally:

sudo start /etc/init.d/cron